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The periodically fully developed laminar heat transfer and fluid flow of an array of non‐uniform plate length, aligned at angles to air flow direction, have been investigated by numerical analysis in the Reynolds number range from 15 to 410. To implement the periodic boundary condition in both streamwise and spanwise directions and to confine the computation exactly within one cycle, proposes a linear interpolation technique, which has been proved successful by comparing the results with those obtained in an extended domain. It has been found that with an increase in the ratio of the long plate length to that of the short plate and with a decrease in the ratio of the transverse pitch to the streamwise cycle length, both the Nusselt number and friction factor decrease. Comparison of the numerical results of Nusselt number and friction factor with relevant experimental results have been performed. The agreement should be judged reasonably good.

To solve the problems caused by using precise molds for copper column positioning in the current column grid array package, this paper aims to optimize the proposed friction plunge micro-welding (FPMW) technology without mold assistance, to overcome the problems of low interfacial bonding strength, shrinkage cavities and flash defects caused by the low hold-tight force of solder on the copper column.

A pressurizing device installed under the drill chuck of the friction welding machine is designed, which is used to apply a static constraint to the solder ball obliquely downward to increase the hold-tight force of the peripheral solder on the copper column during welding and promote the friction metallurgical connection between them.

The results show that the application of static constraint during welding can increase the compactness of the solder near the friction interface and effectively inhibit occurrences of flash, shrinkage cavities and crystal defects such as vacancies. Therefore, compared with the unconstrained (UC) FPMW, the average strength of the statically constrained (SC) FPMW joints and aged SC-FPMW joints can be increased by 51.1% and 122.6%, and the problem of the excessive growth of the interfacial connection layer in the UC-FPMW joints during aging can be effectively avoided.

The application of static constraint effectively inhibits the occurrence of defects such as shrinkage cavities, vacancies and flash in FPMW joints, and the welding quality is significantly improved.

In a supersonic aircraft, a fuselage, a plurality of aerofoils fixed relative to said fuselage including top and bottom surfaces, said aerofoils being longitudinally spaced from the centre of gravity of said aircraft, means for selectively creating supersonic aerodynamic wave patterns over a major portion of said aerofoils whereby differences in pressure result between the top and bottom surfaces of said aerofoils to control said aircraft in flight including a member extensible from the aircraft into the airstream and located adjacent each of said aerofoils, said member comprising a pair of toggle links having a common connexion breakable toward and movable into the free airstream, means for pivotally supporting the end of one of said links on said fuselage, means for biasing the free end of the other of said links in juxtaposition with said fuselage in all positions of said toggle, and means for selectively moving said common connexion into and out of said airstream.

TO say that the Twenty‐fourth S.B.A.C. Show was an unqualified success is perhaps to gild the lily. True there were disappointments— the delay which kept the TSR‐2 on the ground until well after the Show being one—but on the whole the British industry was well pleased with Farnborough week and if future sales could be related to the number of visitors then the order books would be full for many years to come. The total attendance at the Show was well over 400,000—this figure including just under 300,000 members of the public who paid to enter on the last three days of the Show. Those who argued in favour of allowing a two‐year interval between the 1962 Show and this one seem to be fully vindicated, for these attendance figures are an all‐time record. This augurs well for the future for it would appear that potential customers from overseas are still anxious to attend the Farnborough Show, while the public attendance figures indicate that Britain is still air‐minded to a very healthy degree. It is difficult to pick out any one feature or even one aircraft as being really outstanding at Farnborough, but certainly the range of rear‐engined civil jets (HS. 125, BAC One‐Eleven, Trident and VCIQ) served as a re‐minder that British aeronautical engineering prowess is without parallel, while the number of rotorcraft to be seen in the flying display empha‐sized the growing importance of the helicopter in both civil and military operations. As far as the value of Farnborough is concerned, it is certainly a most useful shop window for British aerospace products, and if few new orders are actually received at Farnborough, a very large number are announced— as our ’Orders and Contracts' column on page 332 bears witness. It is not possible to cover every exhibit displayed at the Farnborough Show but the following report describes a wide cross‐section beginning with the exhibits of the major airframe and engine companies.

Laminar fully developed periodic heat transfer and fluid flow characteristics in corrugated two‐dimensional ducts with constant cross‐sectional area are numerically investigated. The governing equations are solved numerically by a finite‐volume method for elliptic flows in complex geometries using colocated variables and Cartesian velocity components. The results were obtained for a uniform wall temperature for two inclination angles and three duct aspect ratios (H/L) and for Reynolds number ranging from 30 to 1200. The plot of the velocity vectors show a complex flow pattern. Unexpected high enhancement of the average Nusselt number was observed at low Reynolds number for H/L = ½ and ⅓. A moderate increase in Nusselt number was obtained as Reynolds number was increased further.

Particle velocity is a critical factor that can affect the deposition quality in manufacturing processes involving the use of a laser source and a powder‐particle delivery nozzle. The purpose of this paper is to propose a method to detect the speed and trajectory of particles during a laser deposition process.

A low‐power laser light sheet technique is used to illuminate particles emerging from a custom designed powder delivery nozzle. Light scattered by the particles is detected by a high‐speed camera. Image processing on the acquired images was performed using both edge detection and Hough transform algorithms.

The experimental data were analyzed and used to estimate particle velocity, trajectory and the velocity profile at the nozzle exit. The results have demonstrated that the particle trajectory remains linear between the nozzle exit and the deposition plate and that the particle velocity can be considered a constant.

The use of low‐power laser light sheet illumination facilitates the detection of isolated particle streaks even in high‐powder flow rate condition. Identification of particle streaks in three subsequent images ensures that particle velocity vectors are in the plane of illumination, and also offers the potential to evaluate in a single measurement both velocity and particle size based on the observed scattered characteristics. The method provides a useful simple tool to investigate particle dynamics in a rapid prototyping application as well as other research fields involving the use of powder delivery nozzles.

Turbulent fully developed periodic heat transfer and fluid flow characteristics in corrugated two‐dimensional ducts with constant cross‐sectional area are numerically investigated. The governing equations are solved numerically by a finite‐volume method for elliptic flows in complex geometries using collocated variables and Cartesian velocity components. Two different turbulence models (the second moment closure and the k—ε) for approximation of the Reynolds stresses are applied. The performance of the models were assessed by comparing the results with experimental data. The results show the advantages of the stress closure model compared to the k—ε model. The overall Nusselt number and the pressure drop ratio results are obtained for the boundary condition of a uniform wall temperature for two inclination angles ø and two duct aspect ratios (H/L) and for Reynolds number ranging from around 3000 to 35,000. The overall Nusselt number predicted by the k—ε model is upto 25% higher than the values predicted by the second moment closure. The plots of the velocity vectors show a complex flow pattern. The mechanisms of heat transfer are explained by the flow phenomena separation, deflection, recirculation, and reattachment.

AS a preliminary to the detail description of the Harrier V/S.T.O.L. Operational Trainer — designated Harrier T. Mk. 2 — it is worth recalling that Hawker Siddeley first made proposals for a dual version of the P.1127 as early as September 1960 (Fig. 1). However, due to the relatively small number of early P.1127 and Kestrel aircraft, efforts to introduce a trainer proved abortive until the Harrier G.R. Mk. 1 production order materialised, following the batch of six Harrier development single seatcr aircraft. A feasibility study for a V/S.T.O.L. Dual Version Harrier was submitted to MinTech in September 1965. This was followed up by a project study in April 1967, which culminated in firm orders for two development two‐seater aircraft, to be followed by a batch of production aircraft.

GRADUALLY, industrial leaders are becoming optimistic. Business chiefs on both sides of the Atlantic are saying that, at long last, they can see the light at the end of the tunnel.

Pyrotechnic effects and spectacular death belong to the symbolism of terror and political assassination – bizarre techniques of miscommunication through fear practiced on the innocent and designed to effect social change. While focusing on the use of terror in 9-11, this article deals with both terror and political assassination as closely related communicative practices of death. It outlines a theory of terrorism that suggests September 11 may be an example of expedient terrorist destruction ordered from within the state, a macabre instance of a state protection racket. Commentators on the left tend to see terrorism as a blow extended by the oppressed against exploiters. However, terrorism is much less likely to be a manifestation of a revolt by – or on behalf of – the underprivileged than a demonstration of brute force by the state or its agents. Machiavellian state terrorism is terror/assassination performed for reasons different from the publicized ones; often initiated by persons or groups other than those suspected of the act; and – most important – secretly perpetrated by, or on behalf, of the violated state itself. Machiavellian state terror advances the ruling agenda, while disguising itself as the work of individuals or groups opposed to the state's fundamental principles. As an example, the article reviews a mysterious 1971 assassination in Paris that obliquely foreshadows some critical elements of the official story of 9-11. The article underlines the importance of oppositional theorizing: questioning government and looking for connections between events are critical features of what it means to be vitally active in the political universe.